Systemic chemotherapy in appendiceal adenocarcinomas with peritoneal metastases. is it worth it?

The role of systemic chemotherapy (SC) in the management of metastatic appendiceal adenocarcinomas is not defined.Methods: We perform an observational study of patients treated of peritoneal metastases from appendiceal neoplasm between June 2004 and December 2017. They were referred to our hospital for CRS HIPEC. Systemic Chemotherapy regimens were decided by the referring oncologist. We analyze PCI, CC, and use of SC. Overall survival and progression free survival were compared attending to histologic subtype (high- and low-grade adenocarcinomas) and the use of SC.Results: 60 patients were included, 26 were male, median age 63 years (26-81). Median follow-up of 38 months [2-155]. The predominant histologic subtype was mucinous adenocarcinoma (58/60), 1 was colonic type, and 1 adenocarcinoid with signet ring cells. Four patients had extraperitoneal metastases, 2 hepatic metastases (1 with high-grade mucinous adenocarcinoma and 1 with colonic adenocarcinoma), and 2 in the low-grade group developed parenchymal lung disease. Three patients died in the postoperative period. Systemic chemotherapy was administered in 26 patients/57. No difference were observed in the OS and PFS regardless the use of SC in the high- and in the lo-grade groups. Conclusions: The use of SC in low-grade mucinous adenocarcinoma subtype is not supported by our results, and there is no literature date supporting it neither. Palliative SC in high-grade patients deserves of clinical trials for been accepted as standard of care, when benefits are not clearly established by evidence and toxicities are not negligible.